Secondary flue restrainer for condensing water heater

ABSTRACT

A flue restrainer and a method is provided for restraining a secondary flue conduit of a condensing water heater wherein to prevent damage to the connections of the secondary flue conduit during transport and manipulation of the condensing water heater prior to being placed into service. The flue restrainer is an inexpensive, single molded plastics part, which is clamped or friction fitted to the secondary flue during fabrication of the water heater.

FIELD OF INVENTION

The present invention relates to condensing water heaters and more specifically to a secondary flue restrainer for restraining the secondary flue conduit during manipulation of the condensing water heater prior to being placed in service.

BACKGROUND OF THE INVENTION

Domestic and commercial gas-fired water heaters have evolved for improving the efficiency thereof by capturing more of the hot combustion gases from its flue for heat exchange with the water contained in its water holding tank. This has been achieved by providing a secondary flue conduit which takes the hot flue gases from the exit end of the central flue and conducts them in a secondary flue conduit extending inside the water holding tank to create a second pass wherein to continue to extract heat from the flue gases by heat exchange with the water in the holding tank before being released into the atmosphere. As the flue gases cool condensation forms in the secondary flue conduit. A blower draws the flue gases through the primary flue and the secondary flue conduit. By doing so, the efficiency of the water heater is increased and the condensate from the cooling flue gas flows in a downward path through the secondary flue conduit which exits the water holding tank in a lower portion of its tank wall. The flue gases are released to the atmosphere at a reduced temperature and condensate is extracted at the lower end of the water heater outside the water holding tank.

Applicant's pending patent application Ser. No. 14/121,994 filed Nov. 13, 2014 illustrates the connection of a coiled secondary flue pipe supported about the central primary flue by dielectric pipe connectors. Other type of secondary flues and their securement are taught by the prior art. We have noted, that because the secondary flue is a long pipe or conduit extending substantially the length of the water holding tank, damage may occur to the connections of the secondary flue during manipulation of the tank after its leaves the factory where these condensing water heaters are fabricated. Because water heaters are long tubular devices it is easier to transport them at an inclination either on a dolly or by two people. Also, often these water heaters need to be installed in tight areas where the water heater is disposed horizontally or rolled inclined on its circular base. This manipulation of the condensing water heater prior to being placed in service can cause displacement of the secondary flue inside the tank and subject its connection to stress created by the weight of the secondary flue being displaced by the manipulation of the water heater. The stress imparted to the connections can damage the gasket, weld joints and other elements of the connection.

SUMMARY OF THE INVENTION

It is a feature of the present invention to overcome the above mentioned disadvantages of the prior art by a low cost solution comprised by a flue restrainer which is easy to install without the use of fasteners or welding.

Another feature of the present invention is to provide a restrainer which is fabricated has a single part from plastics material and which is easy to attach to the secondary flue without the use of fasteners or welding and which arrests the displacement of the secondary flue during transport and manipulation.

Another feature of the present invention is to provide a simple, low cost, method of restraining the secondary flue of a condensing water heater before it is placed in service.

According to the above features, from a broad aspect, the present invention provides a flue restrainer for condensing water heaters equipped with an internal secondary flue conduit disposed inside the water holding tank of the condensing water heater. The restrainer comprises a support member which has a flue tube engaging portion for restraining engagement with one or more portions of the secondary flue conduit. The support member has an abutment end for abutting engagement with a stationary internal surface of the water holding tank.

According to another broad aspect of the present invention there is provided a method of restraining a secondary flue conduit of a condensing water heater during manipulation of the condensing water heater before being placed into service. The method comprises positioning a flue restrainer for frictional attachment to the secondary flue conduit during fabrication of the condensing water heater to restrict the displacement of the secondary flue conduit during manipulation the condensing water heater.

DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention will now be described with reference to examples thereof illustrated by the accompanying drawings in which:

FIG. 1 is a fragmented perspective view of a condensing water heater of the prior art equipped with a dielectrically insulated secondary tubular flue conduit having a helical tubular section and supported inside the water holding tank between a top dielectric connector and a bottom dielectric connector;

FIG. 2 is a fragmented side view illustrating the construction of the dielectric connector of FIG. 1;

FIG. 3 is a fragmented side view of a first example of the construction of the flue restrainer of the present invention and showing it in frictional engagement with the coil windings of the secondary flue conduit of FIG. 1;

FIG. 4 is a perspective view of the flue restrainer illustrated in FIG. 3;

FIG. 5 is a fragmented top view of a condensing water heater illustrating a second example of the construction of the flue restrainer of the present invention in frictional and clamping engagement with a straight vertical secondary flue conduit disposed spaced from the primary flue of a condensing water heater; and

FIG. 6 is a perspective view of the flue restrainer illustrated in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings there is illustrated at FIG. 1 the construction of a condensing water heater 10 constructed in accordance with the invention describe in our earlier referred to U.S. patent application Ser. No. 14/121,994, which is herein incorporated by reference. As herein shown, the condensing water heater 10 is provided with a secondary flue conduit 11 consisting of a copper tube provided with a helical coil section 12 and a straight section 13 for positioning the helical coil section 12 in a lower portion of the water holding tank 14 where the water is cooler than the top section for better heat exchange of the flue gases passing through the helical coil section with the surrounding water in the tank 14. The secondary flue conduit 11 is secured inside the water holding tank 14 by opposed dielectric tank connectors 15 and 15′.

As herein illustrated, the tank connectors 15 and 15′ are provided with a pressure flange 16 welded spaced from the threaded ends 17 of the secondary flue conduit 11 for pressing a gasket 18 once the connectors are firmly secured to the water holding tank walls by a compression nut 19 threaded on the threaded ends 17 extending out of the tank upper wall 20 and a lower portion of the side wall 21. The connectors are identical at opposed ends of the secondary flue conduit 11 to firmly support the secondary flue conduit in position in the water holding tank. Hot gases 22′ exiting the top end of the central flue 22 are directed into the top end 23 of the secondary flue conduit 11 via an interconnecting channel member 9 and drawn through the secondary flue conduit 11 by a blower 24 mounted on the condensing water heater 10 and in communication with the exhaust flue pipe 25 connected to the exit end of the secondary flue conduit. Has can be seen, the majority of the weight of the secondary flue 11 is in the helical coil section 12 where there is a greater length of the copper tube of which the secondary flue conduit is constructed. Because these water heaters have to be manipulated for transport and installation, the secondary coil is subjected to vibrations, such as is generated during the displacement of transport vehicles, often being displaced on rough roads and for long distances, and to side angular displacement of the water heater when transported on dollies or when supported sideways or horizontally prior to installation. Because the weight is in a bundle-like area, the coil section, between the end connectors this weight applies a stressing force on the end connectors 15 and 15′ and this could result in damaging the seal 18 of the connectors and result in leakage and costly repairs has the water holding tanks 11 would have to be drained for replacing the lower gasket.

In order to prevent this stress on the connectors 15 and 15′ it is necessary to restrain the secondary flue from applying stress on its connectors during transport and manipulation of the condensing water heater 10. This is accomplished by the flue restrainer 30 of the present invention as illustrated in FIGS. 3 to 6, wherein two examples of its construction is illustrated. The flue restrainer 30 of the present invention is a simple and inexpensive component which does not require any permanent connections to the secondary flue or any internal part of the water holding tank 14. It is securable to the secondary flue by snap-fit or friction fit connection to the secondary flue.

With reference to FIGS. 3 and 4, there is illustrated a first example of the construction of the flue restrainer 30. As herein illustrated, the flue restrainer 30 is constituted by a flat support plate 31 formed of plastics material, which plastics material has properties suitable for maintain its rigid shape in the hottest water to be contained in the water holding tank 14, typically 120 degree F. to 150 degrees F. It can also be used in domestic or commercial water heaters or boilers. The plate has a thickness of about half inch to assure its rigidity and is molded in one piece from polypropylene or polysulphite or from other equivalent suitable plastics. As herein shown, the support plate 31 has a flue tube engaging portion 32 formed with flue tube engaging jaw formations 33 spaced apart a distance equivalent to the distance between the coil windings 12′ of the helical section 12. The jaw formations 33 are u-shaped formations defining a throat section shaped for receiving a transverse portion of a respective tube of the coil windings 12′ and in close fit therein for clamping engagement or friction fit engagement. A pair of clamping fingers 34 at the mouth of the throat section embrace the transverse portion of the coil in friction fit to prevent the jaw formation 33 from detachment after its engagement with the coils.

The support plate 31 of the flue restrainer 30 defines a support plate extension brace arm which is shaped for restraining abutment in a lower surrounding through 36 defined between the outer periphery of the top wall 37 of the combustion chamber 38 of the water holding tank 14 and the surrounding side wall 14′ of the tank 14. The flue restrainer 30 is clamped onto the helical section 12 after the secondary flue conduit 11 has been secured inside the water holding tank from the open bottom end of the tank. Thereafter, the top wall 14′ of the combustion chamber, which constitutes the bottom wall of the tank 14, is fitted into position and welded about the tank side wall 14′ as indicated by weld 39. The flue restrainer 30 extends substantially vertically within the tank with the free end 35′ of the extension arm section 35 in abutment against an internal surface of the water holding tank.

With reference now to FIGS. 5 and 6 there is shown another example of the construction of the flue restrainer, herein flue restrainer 40. It is also a molded part formed of plastics material and it is adapted to restrain a vertical secondary flue conduit 41 which extends into the water holding tank 14 and spaced substantially parallel to the primary flue 42. As herein shown, the flue restrainer 40 also defines a jaw formation 43 of u-shaped profile defined between a pair of clamping fingers 44. The clamping fingers define a throat opening 45 between them and dimensioned to receive there between a transverse section of the secondary flue conduit 41 for frictional and clamping engagement of the secondary flue conduit in the jaw formation 43.

The flue restrainer 40 also defines an extension brace arm 46 of predetermined length formed integral with the jaw formation 33 and extending rearwards thereof in a common plane. The length of the extension brace arm 46 spans the distance between the outer surface of the secondary flue conduit 41 and the inner surface 14″ of the water holding tank 14. The free end 47 of the extension brace arm has a slightly convex face for smooth contact with the inner face 14″ of the water holding tank side wall 14′ which is usually coated with a glass liner. In order to firmly arrest the secondary flue conduit 41 in position within the tank, one of the clamping fingers 44 may be provided with an extension free end dimensioned for abutment against the primary flue 42 wherein the secondary flue conduit 41 is retained captive between the rigid primary flue 42 and the inner surface 14″ of the side wall 14′ of the water holding tank 14. If desired two or more of these flue restrainers 40 may be attached to the secondary flue without affecting the performance of the condensing water heater. If the secondary flue consists of two or more conduits disposed with the water holding tank and projecting from a manifold combustion gas distributor, then a flue restrainer can be attached to all of the conduits or at least a few of them

Concluding, the present invention provides a novel and inexpensive method of restraining a secondary flue conduit of a condensing water heater to prevent damage to the secondary flue attachments during manipulation and transport of the water heater prior to being placed in service. The flue restrainer 30 and 40 is inexpensive to produce, easy and quick to install as it is snap or friction fitted onto the secondary flue conduit(s) eliminating any permanent connections to the secondary flue conduit as well as to internal parts of the water holding tank, such as by welding or the use of fasteners.

It is within the ambit of the present invention to cover other modified configurations of the flue restrainer depending on the secondary flue conduit construction, provided such modifications fall within the scope of the appended claims. 

1. A flue restrainer for condensing water heaters equipped with an internal secondary flue conduit disposed inside a water holding tank of said water heater, said restrainer comprising a support member having a flue conduit engaging portion for restraining engagement with one or more portions of said secondary flue conduit, and an abutment end for abutting engagement with a stationary internal surface of said water holding tank.
 2. The flue restrainer as claimed in claim 1 wherein said support member is a flat support plate formed of plastics material having properties suitable for maintaining its rigid shape in hot water to be contained in said water holding tank of a domestic or commercial condensing water heater.
 3. The flue restrainer as claimed in claim 2 wherein said plastics material is one of polypropylene or polysulphite or equivalents thereof.
 4. The flue restrainer as claimed in claim 1 wherein said flue conduit engaging portion has one or more flue conduit engaging formations.
 5. The flue restrainer as claimed in claim 4 wherein said one or more flue conduit engaging formations is a jaw formation having a throat section shaped for reception of a section of said secondary flue conduit, said abutment end being located at a free end of an extension brace arm section of said support plate for abutment against said internal surface of said water holding tank.
 6. The flue restrainer as claimed in claim 5 wherein said jaw formation has a mouth opening defined between a pair of clamping fingers dimensioned for frictional engagement with the outer surface of said section of said secondary flue conduit.
 7. The flue restrainer as claimed in claim 6 wherein at least one of said clamping fingers has an extension free end for abutment against said primary flue wherein said secondary flue conduit is retained captive between said primary flue and said internal surface of said water holding tank, said internal surface being an internal surface of a side wall of said water holding tank.
 8. The flue restrainer as claimed in claim 5 wherein said secondary flue conduit has a helical tubular section formed by two or more coil windings, each said coil windings being spaced from adjacent coil windings, there being at least two of said jaw formations disposed side-by-side and spaced apart a distance substantially the same as the distance between said coil windings for frictional and clamping engagement of said jaw formations on associated ones of said coil windings with said support plate extending substantially vertically in said water holding tank.
 9. The flue restrainer as claimed in claim 8 wherein said support plate extension brace arm is shaped for restraining abutment in a lower surrounding through defined between a top wall of a combustion chamber of said water holding tank and a surrounding side wall of said water holding tank.
 10. The flue restrainer as claimed in claim 5 wherein said jaw formations are dimensioned for friction fit engagement with said section of said secondary flue conduit.
 11. The flue restrainer as claimed in claim 5 wherein said secondary flue conduit is secured in said water holding tank by a top connection for receiving hot combustion gases from a top end of said primary flue and a bottom connection connected to a lower end portion of a side wall of said tank for exhausting combustion gases having been reduced in temperature by heat exchange with water in said water holding tank in contact with said secondary flue conduit, said flue restrainer restricting displacement of said secondary flue conduit due to manipulation of said water heater prior to its placement in service and thereby preventing stress on said top and bottom connections by movement of said secondary flue conduit during manipulation of said condensing water heater.
 12. A method of restraining a secondary flue conduit of a condensing water heater during manipulation of said condensing water heater before being placed into service, said method comprising securing a flue restrainer to said secondary flue conduit during fabrication of said condensing water heater to prevent the displacement of said secondary flue conduit during said manipulation of said condensing water heater.
 13. The method according to claim 12 wherein said flue restrainer is a support member having a secondary flue conduit engaging end for restraining engagement with one or more portions of said secondary flue conduit, said method comprising frictionally engaging said flue tube engaging end with said one or more portion of said secondary flue conduit.
 14. The method according to claim 13 wherein said flue restrainer support member has an opposed abutment end for abutting engagement with a stationary internal surface of said water holding tank, said method comprising automatically disposing said abutment end in contact with said stationary internal surface after installation of said secondary flue conduit in said water holding tank. 